Simple, Complex, and Compound Sentences Exercises.pdf
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1. Quantification and risk assessment evaluation of the
neurodegenerative cyanobacterial toxin
β-N-methylamino-L-alanine in irrigation water
sources, fish, and food plants in Sohag governorate.
مي بيتا السيانوبكتريا لسم الخطر وتقييم تقدير
ثيل
في العصبي التنكسي لمرض المسبب أالنين أمينو
في الغذائية والنباتات واألسماك الري مياه مصادر
سوهاج محافظة
2. Presented by
Hanan Mohamed Ahmed Badawye
Department of Botany and Microbiology
Faculty of Science
Sohag University
3. Under Supervision of
Prof. Dr. Zakaria A. Mohamed
Professor of Microbiology/Algal toxins
Department of Botany and Microbiology,
Vice Dean of Faculty of Science, Sohag University
Prof. Dr. Vitor Vasconcelos
Professor of Toxicology and Biotechnology
Department of Biology, Faculty of Science,
Director of CIIMAR - Interdisciplinary Center of Marine and Environmental
Research, University of Porto, Portugal
4. Introduction
Cyanobacteria are the first oxygenic photosynthetic
microorganisms on earth and have contributed to
production of oxygen in the Earth’s atmosphere over
the past 3 billion years (Rasmussen et al 2008).
They can be found in freshwater, terrestrial, brackish,
and marine habitats (Thajuddin and Subramanian,
2005).
Cyanobacterial blooms are of great ecological
significance because of their production for
cyanotoxins, which adversely affect animals, plants and
human health. (Paerl et al 2016; Huisman et al 2018;
Gene et al 2019; Shahmohamadloo et al 2020)
5. Cyanobacterial Toxins
Cyanotoxins are commonly classified in three
classes according to their toxicological target(
Codd et al. 2005).:
(i) Hepatotoxins that act on
liver (e.g., microcystins and
nodularin and
cylindrospermopsin)
(ii) Neurotoxins that cause
injury on the nervous system
(e.g., Anatoxins, Saxitoxins
and β-Methylamino-L-
Alanine–BMAA)
(iii) Dermatoxins that cause
irritant responses on contact
(Lypopolysaccharide,
Lyngbyatoxins and
Aplysiatoxin) ( Codd et al.
2005).
7. β-N-methylamino-L-alanine (BMAA)
BMAA is a non-protein amino acid which has molecular mass of
118.1 Da.
It is a polar basic amino acid with pKa values of 2.1, 6.48 and 9.70
for carboxyl group, primary and secondary amino group (Norden
2007).
BMAA has structural isomers which were observed in natural
matrices are 2,4-diaminobutanoic acid (DAB), N- (2-aminoethyl)
glycine (AEG) and β-amino-N-methylalanine (BAMA) (Figure 1).
8. Forms of BMAA in natural matrices
In natural matrices, BMAA can be present both as a free
compound and/or in protein-bound form.
Therefore, the analytical method should be selected wisely
to determine the concentrations of those fractions separately
or as total BMAA(Murch et al, 2004).
9. Mechanisms of BMAA-induced neurotoxicity
• It has been hypothesized that BMAA neurotoxicity occurs via
glutamate excitotoxicity ((Delcourt et al., 2018; Sini et al. 2021)
• BMAA acts as a glutamate agonist& binds to glutamate receptors (iGluR and mGluR) in the
postsynaptic neuron excessive stimulation of neurons intracellular level of Ca ions
stress on ER and eventually apoptosis (programed cell death caused by caspase enzymes in
mitochondria)
• The binding of BMAA to the glutamate mGluR can activate a Src kinase and inactivate PP2A
hyperphosphorylated tau. Tau is a microtubule associated protein responsible for stabilizing
microtubules. Hyperphosphorylated tau proteins aggregate within cells, forming neurofibrillary
tangles, a hallmark of Alzheimer’s disease.
10. The second hypothesis of BMAA neurotoxicity is that this toxin
BMAA enters neurons and can be misincorporated into proteins,
especially as a substitute for serine, leading to misfolding and
aggregation (signs of Alzheimer’s disease) (Korn et al. 2020, and
Figure 2).
11. BMAA-Producing Cyanobacteria
Cyanobacteria are the main producers of BMAA toxins. All
five known morphological groups/orders of cyanobacteria
(Chroococcales, Pleurocapsales, Oscillatoriales, Nostocales
and Stigonematales) can produce BMAA toxin (Cox et al,
2005)
BMAA and its isomers (DAB and AEG) were found to be
produced by cyanobacteria belonging to 29 genera (Lopicic
et al. 2022).
Nevertheless, this toxin has also been detected in a few species
of dinoflagellates and diatoms (Lage et al., 2014; Reveillon et al.,
2016; Main et al., 2018;; Violi et al., 2019a,b).
12. Cyanobacterial genera which produce BMAA
.Anabaena,Anabaenopsis ,Aphanizomenon, Calothrix,
Chlorogloeopsis, Chroococcidiopsis, Cyanobium,
Cylindrospermopsis ,Fischerella,Gomphosphaeria,
Leptolyngbya, Lyngbya,Microcoleus, Microcystis,
Myxosarcina, Nodularia, Nostoc, Oscillatoria,
Phormidium, Planktothrix, Plectonema,
Prochlorococcus, Pseudanabaena, Scytonema,
Symploca, Synechococcus, Synechocystis,
Trichodesmium and Woronichinia. Omit this slide
13. Accumulation of BMAA in fish and aquatic animals
BMAA can transfer from cyanobacteria to zooplankton and accumulate in
various vertebrates and invertebrates in aquatic ecosystems leading to potential
human exposure(Brand et al., 2012; Mondo et al., 2012) .
Fish can be exposed to cyanobacteria and cyanotoxins through:
1. Active oral route during drinking and feeding on toxic cyanobacterial cells.
2. Passive route through direct contact of the gill epithelium with the dissolved
toxins in the surrounding water(Svirčev et al., 2015) .
These toxins can bioaccumulate in aquatic animals (e.g., fish) and humans
(Dyble et al., 2011) .
14. Humans can be exposed to cyanotoxins via
consumption of fish that accumulate these toxins in
their edible tissues as most cyanotoxins are highly
stable compounds and toxicity is not reduced by
cooking (Zhang et al., 2010).
Previous studies reported the accumulation of the
cyanotoxins: microcystins and cylindrospermopsin
toxins in the edible tissues of tilapia fish collected from
fishponds containing cyanobacterial blooms(Mohamed
et al, 2020).
However, no study has been made on the detection of
BMAA toxin in Egyptian freshwaters yet.
Accumulation of BMAA in fish and aquatic animals
15. Irrigation with contaminated water or using cyanobacterial
blooms as a biofertilizer may result in the exposure of crop
plants to cyanotoxins (Contardo-Jara et al., 2014; Mohamed
et al., 2022; Weralupitiya et al., 2022).
BMAA uptake and accumulation has been documented in
some crop plants including watercress (Nasturtium
officinale) and wild carrot (Daucus carota), wheat (Triticum
aestivum), Chinese cabbage, alfalfa (Medicago sativa),
Lactuca sativa, and Allium fistulosum ( add the references
Accumulation of BMAA in crop plants
16. Actually, the majority of prior studies on the transfer of BMAA from water to terrestrial
plants was carried out in pots under laboratory circumstances or even in the field under preset
experimental conditions (Weralupitiya et al. 2022).
This urges the necessity to provide evidence of BMAA bioaccumulation in plants grown
naturally in agricultural lands irrigated with contaminated water.
The Nile River and irrigation canals branched from it, might be an ideal place to carry out
such field studies.
These irrigation water sources are typical eutrophic waters with frequent toxic cyanobacterial
blooms, due to increasing anthropogenic activities over the past few decades(Mohamed et al.,
2015, Mohamed, 2016).
Studies on other cyanotoxins like MCs and CYN were largely explored in the Nile River and
irrigation water sources in Egypt (Mohamed, 2016), while the BMAA toxin in Egyptian
irrigation waters remains to be demonstrated.
Accumulation of BMAA in crop plants
17. AIM OF THE WORK
The aim of the present study:
• To investigate BMAA toxin for first time in
Egyptian freshwaters, and its potential
transfer to fish and crop plants.
18. Objectives
1. Detection of BMAA toxin in fishpond and irrigation waters
2. Identifying the cyanobacterial species producing BMAA toxin in fishpond
and irrigation waters
3. Determining BMAA concentrations accumulating in edible muscles of
tilapia fish
4. Determining BMAA concentrations accumulating in edible parts of crop
plants
5. Evaluating the potential risk of BMAA in fish and plant tissues on human
health
20. • The present study was conducted in 22 different
irrigation water sites in canals branching and
receiving water from the Nile River, a site on the Nile
River and one fish farm, These sites included a
fishpond (S-19), which serves as a farm for tilapia
fish cultivation, and its water is also utilized for
irrigation of the surrounding plants. These irrigation
canals and the fishpond are located at Sohag
province, southern Egypt (Figure 3).
Locations of the study sites
21. Figure 3. Geographical location of the 22 sampling sites
monitored in the present study.
22. Water and phytoplankton samples
Water samples were collected from the 22 different sites,
Water samples were taken using sterilized polyethylene
bottles at a depth of around 0.3m during summer 2021 and
winter 2022.
500 mL of Phytoplankton samples were fixed and stored
in 1% Lugol's solution.
Sampling
23. Fish samples
• Triplicate samples of tilapia fish (Oreochromis niloticus) were collected from different
sectors in the fishpond.
Samples of cereal and vegetable plants
• Seeds of cereal plants including corn (Zea mays L), sorghum (Sorgum bicolor L) and
wheat (Triticum aestivum L)
• And edible portions (i.e., leaves or fruits) of nine vegetable plants including green
pepper (Capsicum annuum), lettuce (Lactuca sativa), mulukhiyah (Corchorus
olitorius), pea (Pisum sativum), radish (Raphanus sativus), spinach (Spinacia
oleracea), tomato (Solanum lycopersicum), watercress (Nasturtium officinale) and
zucchini (Cucurbita pepo) were collected (after harvest) from farmlands close to
these canals where their waters are utilized for the irrigation of these plants.
Sampling
24. Physico-chemical properties
Physical properties analyses of fishpond waters
including temperature, pH, electric conductivity,
and dissolved oxygen (DO) were measured in situ
before water sampling using multiparametric
probe (HI 991300 pH/EC/TDS Temperature,
HANNA, Italy).
Nutrient concentrations (e.g., nitrate, ammonia,
orthophosphate, dissolved organic matter) were
determined in filtered water samples (through
GF/C glass fiber filter) using standard methods
according to APHA (1995).
25. Phytoplankton analyses
• Phytoplankton cell density was determined using a
Sedgwick–Rafter counting chamber under a compound light
microscope and expressed as cells per liter (APHA, 1995).
Phytoplankton species were identified morphologically based
on pertinent taxonomic keys (Komarek and Komarkova, 2003;
Komárek and Anagnostidis, 2005).
26. Extraction of BMAA
BMAA extraction
Extraction of BMAA in
phytoplankton and
water samples
Extraction of BMAA
accumulated in edible
fish tissue
Extraction of BMAA
accumulated in
vegetable and cereal
plants
27. • Free BMAA and protein-bound BMAA were extracted from
phytoplankton cells, fish muscles ,cereal seeds and vegetable plants
following the procedure outlined in Jiang et al. (2014) with a minor
modification.
• Briefly, an aliquot (one liter) of phytoplankton samples was filtered
through GF/C filters.
• Tilapia fish were rinsed with tap and distilled water to remove any
toxins possibly attached to their surfaces.
• Leaves and fruits of vegetable plants and seeds were washed with
tap and distilled water to remove any potential contaminants that
may have stuck to their surfaces.
Extraction of BMAA
28. Phytoplanktons, Fish
muscles ,ground seeds ,
Leaves and fruits of
vegetable plants extracted
with 20 ml methanol (20%)
sonication for three minutes
(70% efficiency
centrifuged for 5 min (4100 x
g, 4°C).
The pellet was discarded,
supernatant was combined
with two volumes of cold
acetone.
precipitate overnight at
−20°C, and was centrifuged
again (10,000x g, 4°C, 10
min).
pellet containing the protein-
bound BMAA fraction and the
supernatant containing the
free-BMAA fraction were
separated into different new
tubes.
The protein pellet was
hydrolyzed in 1.5 ml of 6 mol
L−1 HCl for 20 h at 110°C
centrifuged for 5 min
(10,000x g,4°C)
The resultant supernatant
containing bound BMAA was
exposed to sterilized air to
evaporate the organic
solvent.
BMAA concentration was
then determined in the
residual aqueous fraction
Extracellular dissolved BMAA
was determined directly in
the filtrate of the same
phytoplankton samples
without any further process.
All samples were stored at
−20°C until use for LC-MS/MS
analysis.
اتجاه توضيح مطلوب
االسهم
29. BMAA analysis
HPLC analysis was performed on using an Agilent 1200
HPLC-DAD coupled with a variable wavelength diode-
array detector (Cox et al. 2003) (Agilent, USA).
The limits of detection (LOD) and limits of quantification
(LOQ) were 4.7 and 10.0 ng, respectively.
Additionally, liquid chromatography-ion trap tandem mass
spectrometer (LC-MS/MS) was used for confirmation and
accurate quantification of BMAA in the samples following
the method described in the method described in Wang et
al. (2021).
30. Risk assessment and potential health hazards of BMAA toxin
The noncarcinogenic human health risk of BMAA was assessed using the reference dose (RfD,
40µg -1 kg-1 d-1) of this toxin, which was previously calculated by Wu et al. [2019] for risk
assessment of BMAA toxin in aquatic products to human health in China based on NOAEL value
of 40 mg kg-1 bw d-1 from the toxicity test data of BMAA for male cynomolgus monkeys
published in Karlsson et al. (2013)
• This RfD was used to estimate guideline value (GV) of this toxin in edible fish muscles, corn
seeds and vegetables according to the country traditions for the consumption of each comestible
(e.g., fish, corn flour and vegetables) using the following equation:
GV =
𝑅𝑓𝐷 𝑥 𝐵𝑊 𝑥 𝐴𝐹
𝐹𝐼𝑅
o GV is the recommended limit for BMAA (μg g-1) for each person per day
o AF is an empirical coefficient, with value set as 0.38 (AF= 0.3÷0.8), indicating that 30% of the
total daily intake of BMAA in humans comes from fish, corn flour or vegetables and the oral
bioavailability of BMAA is 80% as reported by Duncan et al (1992).
o BW is the average body weight (60 kg for adults and 15 kg for children)
o FIR is the food intake rate
o FIR is 100 g for both adults and children of fish per day
o FIR is 200 g for adults and 100 g for children of vegetables per day
o FIR is 300 g for adults and 200 g for children of bread per day
31. Statistical analysis
Differences in cyanobacterial abundance, environmental
variables, and BMAA concentrations in phytoplankton
samples, fish, crop plants and vegetables were analyzed using
ANOVA (P<0.05) with SPSS17 software for windows.
The correlation between cyanobacterial abundance and BMAA
concentrations in phytoplankton and vegetables were tested
using spearman rank correlation coefficients.
33. Physico-chemical properties
• The results showed no difference in temperature, or pH
between the study sites (P>0.05).
• There were significant differences (P<0.01) between the
sites in nutrient concentrations such as NO3 TDS, DOM,
NH4 and PO4.
• However, these parameters showed significant variation
(P<0.05) between summer and winter seasons.
35. Physico-chemical properties and Cyanobacteria
• Irrigation waters were characterized by considerable levels
of nutrients (NO3, PO4 and DOC) as well as suitable
temperature (>25◦C) and pH (>7) that promoted the growth
of and dominance of cyanobacterial species in summer
(Reynolds 2006; Hai et al. (2019)
• Cyanobacterial blooms found in irrigation water sites
during summer, were replaced by Chlorophyta and diatoms
in winter, concurrent with the decline in water temperature
(≤15 °C)
36. Dominance of BMAA-producing cyanobacteria in
irrigation waters
Cyanobacteria dominated phytoplankton populations in
irrigation water (71-100%) during summer (Table 2), while
they were recorded only at three sites:S-2, S-8, and S-19
during winter, but with low percentages (3.3, 6.2 and 9%,
respectively)
• 14 cyanobacterial species dominated phytoplankton
populations and contributed largely to cyanobacterial blooms
in irrigation water sites during summer (Table 2).
• In winter, cyanobacteria were found only in three sites (S-2, S-
8, S-19) and represented only by two species (Plx. rubescens
and Synechococcus elongatus).
39. Figure 4. Light microscope photographs
of dominant cyanobacteria recorded in
irrigation waters during present study:
(a) Aphanocapsa planctonica
(b) Arthrospira platensis
(c) Planktothrix Rubescens
(d) Chroococcus minutus
(e) Phormidium autumnale
(f) Cylindrospermum stagnale
(g,h) Planktothrix agardhii
(i) Dolichospermum lemermmanni
( j ) Nostoc commune
Scale bar =10µm.
40. Cyanobacteria were the dominant
group in phytoplankton samples in the
fishpond during summer (99.4% of the
total phytoplankton).
On the other hand, cyanobacteria
showed lower abundance during
winter season (9.2%) and was
represented only by two species
(Dolichospermum flos-aquae and
Synechococcus elongatus)
Green algae and diatoms were also
found in the fishpond during summer,
but with low cell densities (0.22%,
0.38%, respectively) (figure 5).
Dominance of cyanobacteria in fishpond water
Figure ….. Percentage distribution of
phytoplankton groups in Sohag fishpond
during the present study.
41. Cyanobacterial populations in this fishpond
were dominated by six cyanobacterial
species:
(a)Dolichospermum flos-aquae,
(b)Merismopedia glauca,
(c) Microcystis aeruginosa,
(d)Planktolyngbya contorta,
(e) Raphidiopsis raciborskii,
(f)Synechococcus elongatus.
Scale bar =10µm.
Figure 5. Light microscope photographs of
dominant cyanobacteria recorded in the
studied fishpond during present study:
Dominance of cyanobacteria in fishpond water
42. The figure shows HPLC
chromatograms of BMAA: (a)
standard, (b) free BMAA, (c)
protein-bound BMAA in
phytoplankton samples
collected from the fishpond
during the present study.
BMAA concentrations in fishpond water
43. • The highest concentration of total
BMAA were obtained in phytoplankton
samples collected from the fishpond
during summer (227.66 µg L-1),
• Very low concentrations of BMAA
were in phytoplankton samples
collected in winter (0.1 µg L-1).
• Free BMAA showed higher
concentrations (180.5µg L-1) than
protein-bound form (47.16µg L-1).
• Dissolved extracellular BMAA ws also
detected in in cell-free fishpond water
(0.1µg L-1 in winter & 1.34 µg L-1 in
summer
BMAA concentrations in fishpond water
44. • Edible tissues (i.e., muscles) of
Tilapia fish caught from the
fishpond during summer
contained higher amounts of free
BMAA (65.1µg g-1 FW) than
protein-bound BMAA (8.14µg g-
1 FW).
• Free and bound BMAA were
also found in the edible tissues
of fish collected during winter,
but at very low levels (1.07,
0.087µg g-1 FW, respectively)
BMAA concentrations in tilapia fish tissues
45. • Concentrations of free BMAA
(0.6-11.4 μg L-1) were higher
than protein-bound BMAA
(0.01-3.3 μg L-1) in all
phytoplankton samples collected
during summer
• These concentrations varied
significantly (P< 0.05) among
different sites, and correlated
(r=0.9) with the cell density of
dominant cyanobacterial species
• Extracellular dissolved BMAA
was also detected in cell-free
irrigation water, but with very
low concentrations (0.1-0.2μg L-
1).
BMAA concentrations in irrigation waters
46. • In winter, irrigation water
samples from sites not-
containing cyanobacteria (S-2,
S-8, S-19) did not have any
detectable levels of BMAA.
• Low concentrations of free
(0.2-1.3μg L-1), bound (0.06-
0.17μg L-1) and dissolved
(0.04-0.1μg L-1) BMAA were
found in sites containing the
cyanobacteria: Plx. rubescens
and S. elongatus during winter,
indicating the involvement of
these species in the production
of BMAA toxin in irrigation
water.
BMAA concentrations in irrigation waters
47. • Although 14 cyanobacteria species
These were correlated with BMAA
concentrations in phytoplankton
samples, only these five species
could be cultured in the Lab and
analyzed for their capability for
BMAA production.
• The extracts of pure cultures of
these species contained greater
amounts of free BMAA (4.8-
71.1µg g-1 dry weight) than
bound form (0.1-11.4µg g-1 dry
weight) ,the highest values
produced by N. commune (71.1µg
g-1 dry weight) and lowest by Plx.
rubescens (4.8µg g-1 dry weight)
BMAA production in isolated cyanobacteria
Cyanobacteria BMAA concentrations
(µg g-1 dry weight)
Dolichospermum
lemermmanni
Free Bound
70.4±6.1 11.4±2.1
Aphanocapsa planctonica 9.81±1.8 0.3±0.02
Chroococcus minutus 6.8±1.3 0.1±0.02
Planktothrix rubescens 4.8±0.8 2.5±0.3
Nostoc commune 71.1±3.3 9±1.6
48. • BMAA detected in seeds was
found in bound form only
• BMAA was found only in
corn and sorghum seeds, but not
in wheat seeds-
in concomitance with the absence
of BMAA toxin in irrigation
waters due to the nonexistence of
cyanobacteria during winter.
• BMAA in the seeds of the same
plant varied between the sites of
collection, in association with
BMAA concentrations in
irrigation water (r=0.8-0.9).
BMAA concentrations in cereal grains
Cereals Site Collectio
n season
BMAA concentration
(μg g-1 FW)
Free form Bound form
Corn S-20 Summer ND 3.87±0.7
S-15 Summer
ND
4.51± 0.8
Sorghum S-10 Summer ND 7.1±1.2
S-4 Summer ND 5.1±1.3
Wheat S-13 Winter ND ND
S-3 Winter ND ND
49. • The accumulation of BMAA toxin in
edible parts (leaves or fruits) of 9
vegetable plants collected from
farmlands irrigated with water
containing BMAA-producing
cyanobacteria.
• BMAA was only found in protein-
bound form in all vegetable species,
except for zucchini, which had small
amounts of free BMAA besides the
bound form.
• BMAA concentrations in edible parts
of the same plant varied considerably
(P<0.05) between the collection sites
(i.e., the irrigation water source), and
this variation was correlated with the
amount of free and dissolved BMAA
found in the irrigation water (r=0.8-
0.9).
BMAA concentrations in vegetable plants
Site Season BMAA concentration
(μg g-1 FW)
Free Bound
Green pepper Site 1 Summer ND 1.1±0.4
Site 7 Summer ND 1.5±0.4
Site 21 Summer ND 1.4±0.3
Lettuce Site11 Winter ND ND
Mulukhiyah Site 2 Summer ND 0.35±0.07
Site 3 Summer ND 0.7±0.2
Site 4 Summer ND 0.4±0.06
Pea Site 19 Winter ND 0.05±0.008
Radish leaves Site9 Summer ND 0.83±0.2
Site19 Summer ND 0.61±0.1
Radish roots Site9 Summer ND 0.31±0.07
Site19 Summer ND 0.2±0.05
Spinach Site 5 Winter ND ND
Tomato Site 14 Summer ND 0.93±0.1
Site 21 Summer ND 5.9±1.1
Site 22 Summer ND 0.34±0.06
Watercress Site 8 Summer ND 1.9±0.4
Site 11 Summer ND 5.1±1.2
Site 12 Summer ND 4.7±0.6
site 13 Summer ND 4.98±1.1
Site 18 Summer ND 6.9±1.3
Zucchini Site 8 Winter 1.23±0.2 7.7 ±1.3
50. • Absence of BMAA in spinach
and lettuce, in concomitance
with the absence of BMAA toxin
in irrigation waters at relevant
sites (S-5 and S-11, respectively)
due to the nonexistence of
Cyanobacteria during winter
• Accumulation of BMAA in pea
and zucchini (0.05 and µg g-1
fresh weight, respectively),
receiving water from S-19 and
S-8 containing the toxin (0.2
and 1.33 µg L-1, respectively)
during winter,
BMAA concentrations in vegetable plants
Site Season BMAA concentration
(μg g-1 FW)
Free Bound
Green pepper Site 1 Summer ND 1.1±0.4
Site 7 Summer ND 1.5±0.4
Site 21 Summer ND 1.4±0.3
Lettuce Site11 Winter ND ND
Mulukhiyah Site 2 Summer ND 0.35±0.07
Site 3 Summer ND 0.7±0.2
Site 4 Summer ND 0.4±0.06
Pea Site 19 Winter ND 0.05±0.008
Radish leaves Site9 Summer ND 0.83±0.2
Site19 Summer ND 0.61±0.1
Radish roots Site9 Summer ND 0.31±0.07
Site19 Summer ND 0.2±0.05
Spinach Site 5 Winter ND ND
Tomato Site 14 Summer ND 0.93±0.1
Site 21 Summer ND 5.9±1.1
Site 22 Summer ND 0.34±0.06
Watercress Site 8 Summer ND 1.9±0.4
Site 11 Summer ND 5.1±1.2
Site 12 Summer ND 4.7±0.6
site 13 Summer ND 4.98±1.1
Site 18 Summer ND 6.9±1.3
Zucchini Site 8 Winter 1.23±0.2 7.7 ±1.3
51. • The assessment of noncarcin-
ogenic human health risk of
BMAA estimated during our
study revealed different GV
values for fish, corn and
vegetables (Table )
Risk assessment of BMAA in fish and plants
BMAA GV (µg g-1 FW)
Comestibles
Children
Adults
2.3
9.1
Fish
1.14
3.1
Corn
2.2
4.5
Vegetables
Table Guideline values (GVs) for BMAA
in fish, corn seeds and vegetables based on
toxicological data in earlier studies and
toxicological data of earlier studies and
Egyptian conditions of food consumption
• Results ويوضع رقم له يحدد الجدول هذا
في العنوان هذ تحت
اخر
52. • Compared to these GVs, BMAA
concentrations in edible fish
muscles during summer (73.2 µg g-
1) in our study surpassed these GVs
by a factor of for adults and 32 for
children.
•
• On the other hand, BMAA
concentrations detected in fish
muscles during winter (1.16 µg g-1)
were below these GVs.
• This reflects that tilapia fish
collected in summer during the
prevalence of cyanobacterial
blooms in the fishpond is not safe
for human consumption, while fish
collected during winter is safe and
might not constitute a severe health
risk.
Risk assessment of BMAA in fish
BMAA GV (µg g FW)
Comestibles
Children
Adults
2.3
9.1
Fish
1.14
3.1
Corn
2.2
4.5
Vegetables
53. • BMAA concentrations detected in corn seeds
(3.87-4.51µg g-1) in the present study exceeded
these proposed GVs values
• Long-term consumption of corn products with
toxin levels surpassing the proposed GV may
threaten human health.
• For sorghum (S. bicolor), we could not propose
GV of BMAA for sorghum grains in the
present study because we are not sure how
much it contributes to human food (no
information about AF and FIR)
• However, sorghum grains are also considered a
valuable livestock feed worldwide.
• Therefore, the presence of BMAA in sorghum
seeds could have negative effects on animal
health and possibly leak into milk, adding
another way for humans to be exposed to this
toxin.
Risk assessment of BMAA in cereal grains
BMAA GV (µg g FW)
Comestibles
Children
Adults
2.3
9.1
Fish
1.14
3.1
Corn
2.2
4.5
Vegetables
54. • BMAA concentrations found in
watercress leaves (4.7-6.9µg g-
1 FW), and tomato (5.9 µg g-1
FW) zucchini (7.7 µg g-1 FW)
fruits exceeded the proposed
GV values for both adults and
children,
• While BMAA concentrations
(0-1.5 µg g-1 FW) in other
vegetables (green pepper, lettuce,
mulukhiyah, pea, radish, and spinach )
were below these GVs
Risk assessment of BMAA in vegetables
BMAA GV (µg g
FW)
Comestibles
Children
Adults
2.3
9.1
Fish
1.14
3.1
Corn
2.2
4.5
Vegetables
55. Conclusions
Cyanobacteria dominated phytoplankton populations in the
fishpond and all irrigation water sites during summer, in
association with high temperature and large nutrient
concentrations.
In winter, some species of cyanobacteria (e.g.,
Planktothrix rubescens and Synechococcus elongatus) can
survive in some irrigation water sources at 15-18°C,
indicating that cyanobacteria in water sources would
spread more widely and last longer in the future as a result
of climate change
56. Conclusions
BMAA toxin is found in phytoplankton cells with higher
concentrations of free form than bound one
This issue is of particular concern, as it releases easier
from cells into the surrounding water during natural
senescence or application of algaecides, raising the toxin
burden (i.e., extracellular dissolved toxin) in irrigation
water, which can transfer into plants
Cyanobacteria are the main source of BMAA toxin in the
fishpond and irrigation waters.
57. Conclusions
Accumulation of BMAA in corn and sorghum seeds at
concentrations surpassing the proposed GVs values, for
human consumption of corn flour as bread
As sorghum grains are a valuable livestock feed
worldwide, the presence of BMAA in sorghum seeds could
have negative effects on animal health and possibly leak
into milk, adding another way for human exposure to this
toxin.
58. Conclusions
Vegetable plants such as watercress leaves, tomato and
zucchini fruits accumulated BMAA at concentrations,
exceeding GV values proposed for this toxin for human
consumption of vegetable plants.
Generally, BMAA concentrations in fish tissues and edible
plant parts strongly associated with cyanobacterial cells
density and toxin concentration in irrigation water
59. Recommendations
Aquacultures and fishponds should be monitored for the
presence toxic cyanobacteria and their cyanotoxins,
particularly the regions expected to be impacted by climate
change, which would favor the occurrence of
cyanobacterial blooms (even in winter) and help spreading
some toxin-producing species to latitudes outside of their
usual range.
Strict restrictions must be implemented in aquaculture
systems, and cyanotoxins should be tested in edible fish
tissues taken from eutrophic waters before being sold in
order to protect people from exposure to such potent
toxins.
60. Recommendations
Irrigation water sources worldwide should be shielded
from urban and agricultural runoff to limit the proliferation
of toxic cyanobacteria.
Irrigation water and edible portions of crop plants should
be continuously monitored for the presence of cyanotoxins
to protect the public against the exposure to potent
cyanotoxins through food consumption.
